1. Field of the Invention
The present invention relates to a novel construction of a heat pipe which conveys heat by making use of evaporation and condensation of a liquid, as well as a method of producing the same. More particularly, the invention is concerned with a method of producing a heat pipe suitable for use in the cooling of dynamic electric machines, machine tools or the like apparatus.
2. Description of the Prior Art
A typical known heat pipe is constituted by a closed vessel made of copper, aluminum or the like material and provided in the inner surface thereof with a multiplicity of longitudinal grooves adapted for performing a capillary action. The heat pipe of the type mentioned above is often used at such a gradient that the heated end thereof takes a higher level than the other end. In such a use, the liquid condensed at the colder other end of the heat pipe has to climb up to the heated end by the capillary action, overcoming the force of gravity. Unfortunately, however, the grooves can produce only a small capillary sucking effect, so that the heat pipe can be used only at a slight gradient.
On the other hand, the specification of U.S. Pat. No. 3,543,841 discloses a heat pipe in which the closed vessel is lined at its inner side with a wick to enhance the capillary action. The use of the wick, however, imposes other problems such as a rise in the production cost, greater tendency of clogging and greater resistance to heat transfer.